Hydropower Operations & River Systems Modeling
Green Lake and Blue Lake Hydroelectric Projects Operations Modeling
The
city and borough of Sitka, Alaska owns and operates the Green Lake and Blue Lake
hydroelectric projects. These two projects supply the required load for the
city’s isolated electric system. As system loads increased, the city
needed an effective tool to predict the need for, and minimize the amount of,
diesel engine generation required to supplement the hydroelectric plants.
The city hired Devine Tarbell & Associates (DTA) to modify the city’s proprietary CHEOPS™ model to simulate the city’s combined hydro-diesel generating system and to specifically answer a variety of operations questions. In essence, the city wanted the model to predict whether the current hydroelectric resources could meet future loads assuming user-selected starting reservoir elevations and hydrology.
DTA modeling engineers configured the CHEOPS™ model to accurately simulate the unusual operating constraints of the two projects. Frequency control requirements in the system necessitate a unique scheduling criteria which proved to be a complex modeling challenge. The final model configuration allows the user to select multiple system constraints, which the model simulation must follow.
City of Sitka staff are currently using the model to ascertain the need for alternative generation sources under current and future system loads.